Category Archives: Space Science

A new study on the Red Planet suggests that the sharply etched channels that crisscross its surface may have been cut by frozen CO2, rather than water.

The contention is that these gullies are very much active, and continue to form on Mars even now in cold weather. If that’s the case, than it is almost certainly ‘dry ice’ or frozen CO2 that is developing this geological feature.

Recent photographs captured by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter, have enable a new look at the phenomenon, allowing researchers such as lead author Colin Dundas to examine the timing of gully formation over the last couple of years.

The conclusion was that the gully formation is occurring in winter, when the Martian atmosphere is condensing out as a solid. Unlike Earth, where the temperature and pressure conditions for the formation of dry ice does not occur in nature, on Mars they occur every winter, most notably in the form of a seasonal polar ice cap.

As many as 38 sites have now been identified as showing active gully formation. All at times when it would be too cold for liquid water to flow.

So if your heading out the Red Planet – don’t forget the Beer Cooler. The dry ice is free :).

The lengthening lists of new planet finds have allowed astronomers to start building on the science and knowledge of planet and solar system formation to draw some fascinating conclusions.

According to Astrophysicist Lars Buchhave (Harvard-Smithsonian Centre for Astrophysics) there are three sorts of solar system. The key to the classification system is the elemental composition or ‘heaviness’ of the progenitor nebula – specifically how metallic they are. Rather than the observation of a smooth transition between these three types, the collected data on exoplanets shows distinct types of solar system with little in between.

Planets around the most metallic stars tend to be big – gas giants in the Jupiter class and above. The reason being that the presence of these heavier elements allows more planetary development before the protostar ignites, allowing the growing planet to get heavy enough to attract the lighter elements of hydrogen and helium.

Planets around the least metallic stars tend to be mainly rocky planets, but larger than the rocky planets around our own sun

Those suns in the middle range of metallicity are associated with a third (unfamiliar) type of planet called gas dwarfs. These planets have rocky cores, but are large enough to hold an atmosphere of hydrogen and helium.

So where does our own solar system fit in? Apparently nowhere. Our solar system with our four small rocky planets and four gas giants is an unusual one. In terms of the metallicity spectrum, Earth’s Sun is an example of a metal-rich star, common in the spiral arms of the Milky Way galaxy, so I guess at least our gas giants make sense based on this latest theory.

This got me thinking. Maybe our solar system was formed in the collision of two proto-systems early on? Would this explain the weird fact that Venus rotates in the opposite direction to all the other planets that spun off the ecliptic? Perhaps a metal-poor (Population II) star that went supernova leaving its drifting rocky planets to be snapped up by our Sun?

This oddness in our planetary composition is just the latest in a series of weirdness that relates to our solar system. I’ve noticed this before. The more we look – with the benefit of science – the more atypical we are. Like how both the Moon and the Sun are exactly the same angular size in the sky.

Some of these strange coincidences allowed the development of life as we know it. Jupiter has had a very positive role in protecting life on Earth, acting as our planetary ‘guardian’, preventing many of the asteroid impacts that would have sent life back to the drawing board again and again.